Helmet accessory



FIG. 1 is a front view of a helmet accessory showing my new design;

FIG. 2 is a top view thereof;

FIG. 3 is a side view thereof; and,

FIG. 4 is a front perspective view thereof.

The helmet accessory is shown attached to a helmet, shown in phantom. The helmet does not form a part of the invention. 

The ornamental design for a helmet accessory, as shown and described. 